Cut-in system of radiotelegraphy



P. WARE. l

CUT-IN SYSTEM OF RADIOTELEGRAIHY. APPLICATION FILED FEB. 811918.

1,379,144, mma May 24,1921

*IIIIIIIIIII gIumImF-- I" INVENTOR MWW v- ATTORNEY I UNITED STATES PAUL WARE, OF NEW YORK, N. Y., ASSIGNOR 4'.lO WARE RADIO, INC., A CORPORATION PATENT OFFICE.

F DELAWARE.

CUT-IN SYSTEM or RADIOTELEGRATHY.

Specification of Letters Patent. Patented May 24,1921.

Application led February 8,-1918.` Serial No. 215,996. v i

T0 all wlw-m #may concern.'

Be it known that I, PAUL WARE, a citizen of the 'United States, and resident of New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Cut-In Systems of Radiotelegraphy, of which the following is a specification.

This invention relates to' radi telegraphy e and has for its object to increase the rapidity with which traiiic may\be handled by enabling the receiving station to cut in on the sending station without disturbing the adjustments of the system, and thereby notify 1f the sending station that the message has not been understood.

Much delay is now caused in radio telegraph communication because the receiving operator must wait until the sending operator has signedo'ff before he can communicate with the sending operator. By this invention, the receiving operator can cut in on the sending operator at any time, so that it becomes unnecessary for the receiving'operator to wait until the sending operator has signed off and has put his apparatus in condition for receiving, and the receiving operator' has put his apparatus in condition for sending, before reversing the direction of communication. This invention is ,especiallyy adapted for undamped wave transmis- Asion by the beats method, wherein the frequencies of the sending and receiving stations diier to such extent. that a beat note is producedv at the receiving station. In present methods of radio telegraphy by the beats method, the sending operator does not hear'the beat note, and consequently does not know either Whether his signals are being sent out from his station, or whether they are being received at the other end,

which is the reason for much of the delay above referred to, but with this invention the beats are heard at both ends.

According vto this invention, there is provided in the sending key circuit of each station means whereby the receiving opera'- tor may suppress the beat note, and thereby cutin on the sending operator. and destroy the beat note which he normally hears. In the preferred form herein shown,'the key circuit at the receiving station isnormally closed, and` when the receiving operator desires to cut in, he opens this key circuit. This varies the capacity of the recelvmg circuit and suppresses the beat note which l suppression immediately becomes apparent toIY the sending operator and attracts his attention. The receiving operator can now by further manipulation of his key communicate with the sending operator, or the sending operator can continue his message.`

r[`he sending operator upon not healing. the beat note will close his key circuit so as to be ready to receive the expected message from the receiving station. By having this arrangementl at both stations, it is possible for the` operators to communicate back and forth without requiring the receiving operator to wait until the sending operator has signedcff and'set'his apparatus for receiving before answering back.

This invention will be more fully understood in connection with the description of the accompanying drawings wherein,

Figure 1 shows a diagram of one of the stationsadapted for relatively short distance communication,

Fig. 2 shows a modification especially intended for long distance communication with separate receiving and sendingoscillators, an

Fig. 3 is a diagram of a high power undamped wave stationemploying separated sending and receiving antennae using differcnt wavelengths.

Referring to Fig. 1, 1 represents an` antenna leading through 'an insulating bushing into'- the interior of an electrostatic screen 2, composed of conducting material such as copper or aluminum. Antenna 1 is inductance coil 1 0, which is variably coupled to the antenna tuning coil 3, and then by wire 11 to a. tuning' coil 12, having itftermi.- nal connected by wire 13 through variable capacity 14 to wire 9. The capacity 14 isj l for the' purpose of making the local circuit resonant in case the inherent Acapacity of the audion and the connected apparatus is insuiicient for this purpose. Theplate circuit is also coupled through Wire 15 a-nd'variable capacity 16 to the antenna circuit above the capacity 4. lThe grid 18h is. connected by wire 19 through inductance 32 and wire 33 leading through the screen to external and adjustable 'grid battery 34. The inductances 12 and 32 constitute a variable grid coupling. The remainder of the grid circuit is from Y battery 34 by wire 35 to grid potentiometer tor presses his key downy to send, and a beat 36 and wire 37 to adjustable filament resistance 38 and then by wire 39 to filament 40 and thence by wire 41 to the screen 2.

From the junction of wire 13 and the lower terminal ofl inductance 12 la wire 43 leads through a shielding inductance 44 and wire 45 through the screen to external plate battery 46, thence by wire 47 to the receivers 48, and by wire 49 to the screen. Combined with the shielding inductance 44 are shielding capacities 50 which are connected across inductance 44 by wire 51 to the screen, so that the low frequency or direct current circuits and apparatus outside the screen will be isolated or shielded from the radio frequency currents within the screen, because the inductance 44 and the capacities 50 shunt the radio frequency current to the screen, while the low frequency or direct currents are not affected by the inductance 44. 52V is the heating battery for the filament. The grid circuit is simi. larly connected. v

The key circuit is by wire 55 through adjustable capacityk 56 and wire 57 leading through the screen to-key contact 58, from which there is one path by wire 59 side or breaking in lever 60, and wire 61 to the screen, or ground, andan alternativel path by key 62. 4 The frequencies at the stations differ sufficiently to produce a main or signal beat-note when the keys at each station are closed, sending being done by the kev in the usual manner to produce dots and dTashes. When the -receiving key circuit is opened by raising the key and opening the side lever the antenna circuit will be thrown sufficiently out of resonance with the local circuit coupled therewith as to produce either a different beat note at one or both stations if capacity 56 is very small, or if large, no beat note at all is produced when one or both ke circuitsl is opened. By opening the key circuit is meant o ening both at the key and the side lever. en the receiving operator, for

example, desires to cut in,'he will open his key, and either produce the different beat note in both receivers, orv suppress the signal beat note entirely, depending upon the size of capacity 56. This change in the sending note having the main or signal frequency, attracts the attention of the sending operator, or else interchanges the dots and dashes of the code for spaces, which has the same effect, since there'will be 'a space instead of a beat note when the `sending operanote of 'different tone from the main sending tone will occur with his key up instead of a space or the main sending tone.

Where a complete cut in is desired, the capacity 56 is of such size as to cause the beat note with one key open to be out of audibility range at both stations. This notifies the sending operator that the receiving operator has cut in, and he thereupon holds his key down to receive in the usual manner.

In Fig. 2 is shown a long distance arrangement with separate oscillators producing undamped waves.- At each station the sending apparatus is so arranged that the transmitted energy ldoes not affect the receiving system. This is Vdone by connecting the receiving and sending circuits to the an-l tenna in such manner that the receiving inductance 64 is connected through a divided antenna inductance 65, 66, and the conductor 67 carrying the sending energy is connected between these inductances so as to be without effect on receiving inductance 64. Thus the sending energy is balanced on both sides of inductance 64; by the inductance 66, capacity 4, and ohmic resistance q, on one side; and on the other side, by the antenna inductance, capacity and resistance above the point of connection of Wire 67 to antenna inductances 65, 66. The sending key 68 when down makes contact for sending through wires 69, 70, and has auxiliary contacts connected towires 74, 72, containing capacity 73 across the receiving system. When key 68 is down, capacity 73 is open circuited, and the receiving system is in correct tuning for heterodyne reception, lbut when the key. is up and the circuit 7 2, 73, 74, is closed, capacity'73 is shunted across the receiving tuning capacity 14, thereby throwing the receiving system suiciently out of tune with the received signal as to destroy the beat note. Insending, the wave length is varied by placing the capacity 56 in and out of shunt across coil p.

For best results the tuning for receiving will be effected with keys 62, 68 in Figs. 1, and 2, down.

Fig. 3 shows an arrangement for high powered undamped transmission systems without a balancing system but employing separate receiving and sending antennae 75, 76, and wave -lengths of such difference as to prevent interference. The operating room is usually situated at the receiving antenna, and the sending apparatus is preferably operated by a relay 78. The sending source may be any source ofl oscillations such as an audion, as shown, a high frequency generator, arc, etc., and the receiver may be of any type suitable for sustained or undamped waves, such as an oscillating audion.

In operation, the normal condition is with both keys down and each station operator hears the characteristic beat note, the receivers having been tuned to give the best or the desired beat note. The cut in is effected by lifting or opening one key circuit, whichdetunes both the receiver and transmitter at that station2 and destroys the beat note at the other station by causing it to be out of. tune, or out of audibility range, owing vto the change of frequency caused by the capacity 56 being cut o'ut, 'or rendered inaudible lyhth'e weakening of the radiated power. ere I speak of varying the beat note to indicate a c ut in, I mean to include either suppression of the beat note partially or entirely, or changing it from normal to abnormal Vwithin or without the audibility range, as one or theJ other result may be preferable according to the system in which the invention is applied. l

By this invention, a cut-in at any timev 'permits traiiic to be handled much more rapidly and accurately, and the sending operator can hear his kown message. This is because the beat note caused by the difference between the incoming and the local oscillation is audible at both stations, and the operator desiring to cut-in, canl do so by making his characteristic signal with lhis key or opening his key, which thesending operator will recognize. .The same result occurs if a chopper or other well known means produces the local oscillation at the receiving station. The principle of the invention is applicable in various ways and to various circuits, and I do not restrict myself to the circuits shown herein except as limited by the appended claims.

Matter specific to Figs. 2 and 3 hereof is not claimed herein, but is claimed in divisional applications `filed April 14, 1921, Ser. No. 461,436 and 461,437. v

What is claimed, is:

1. A space radiotelegraph system comprising a plurality of stations each having means for generating outgoing waves, radiating means, means for receiving incoming radiatedwaves, .there being such differv ence in the generated and received waves at from one station and cut in from the receiving station upon actuation of each key respectively. i

' 2. A space radiotelegraph system comprising.- a plurality of stations each having -means for generating outgoing waves, ra-

dlating means, means forrecelving 1ncom-.

ing radiated waves, there being such difference in the generated and received waves at eachv station as to continuously. produce at each station a local signal current, and a key at each station controlling b'oth signal currents in such a manner that said currents are locally manifest only when the keys are in closed positions, whereby to permit sending from one station and cut in from the receiving station upon actuation of each key respectively.

3. A space radiotelegraph system comprising a plurality of stations each having la single. means for generating continuous 'outgoing waves, radiating means, means for receiving incoming radiated waves, there being such 'difference in the generated and received waves at each station as to continuously produce at each station a local signal current, and a key at each station control'- ling both signal currents in such-manner that said currents are locally manifest only when the keys are in like positions, whereby to permit sending'from'one station and cut in from the receiving station upon actuation of each key respectively.

4. A space radiotelegraph system com- -prising a plurality of stations each having a single means for generating outgoing waves, radiating means and receiving means at each station', said means at one of said stations comprising a single element, there being such difference in the generated and received waves at each station as to. continuously produce at each station a local signal current, and a key at each `station controlling both signal currents in such manner that said currents are locally manifest only when the keys are in like positions, whereby to permit sending from one station and cut in from the receivingzstation upon actuation of each key respectively.

5. A space, radiotelegraph system comprising a' plurality of stations each having an audion for generating continuous outgoing waves, radiating means, means for receiving incoming radiated waves, there being such difference in the generated and received waves at each station as to produce b outgoing waves, radiating means, means for receiving incoming radiated waves, there being such difference in the generated and recelved waves at each station as to produce at each station a continuous local signal current of audio frequency, audio frequency apparatus at each station in the plate circult responsive thereto, and a key at each station controlling both signal 'currents in such manner that said currents are locally manifest only when said keys are in like positions, vwhereby to permit sending from one station and cut in from |the receiving station upon actuation of each key respectively.

7. A space radiotelegraph system comprising a plurality of stations each having an audion for generating continuous outgoing waves, radiating means, means for receiving vincoming radiated waves, there being such difference in the generated and received waves at each station as to produce at each station a continuous local signal current of audio frequency, audio frequency apparatus at each station responsive thereto, means for radiating and receiving oscillations of such diil'erence in frequency as to simultaneously produce an audible-beat note at each station, and a key at each station for varying both beaty notes. v

9. In a space radio telegraph system, two stations, receiving and radiating means, a single source of continuous oscillations at each station producing in combination with the oscillations received from the other station a continuous beat note of the same frequency at each station, and a key at each stations each having means for producing,

. station controlling both beat notes.

10. In a space radiotelegraph system, two

stations each having means for radiating and collecting oscillations and a single elementA for generating voutgoing oscillations and detecting incoming oscillations, and a key at each station so arranged as to be normally in like positions for transmission from one station and reception at the other yso that opening of either key effects a signal lat, the other station.

11. A- space radiotelegraph system comprising a plurality of stations with means at each for producing outgoing and collecting and -detecting incoming continuous waves,

there being such diierence in the generated and received waves at each station as to continuously produce an audible beat note at y. each, one station having a' sending key so connected that the, operator thereat hears hisY- own message as sent and the other station having a key controlling thereception which when moved from receiving position varies the beat note at the sending station to effect a signal to the sending operator.

12. A radio telegraph system embodyin' a receiving station, means for isolating radio frequency from certain parts of the circuit containing low frequency apparatus, and a cut-in mechanism 'for interrupting the oscillations and making an indication at the sendino station.

13. radio telegraph system embodying a receiving station, means for isolating ra io frequency from certain parts of the circuit containing low frequency apparatus, and a cut-in mechanism including a key and means controlled thereby for Avarying the oscillations to make an indication of aA cut-in 'at the sending station.

14. A radio telegraph system embodying atI one station an oscillating audion having sending and receiving means connected thereto, means for isolating radio frequency currents from certain parts of the circuit containing low frequency apparatus, and

means for varying the oscillations at the re- 'ceiving station to effect a cut-in at the sending station.

15. A space radio telegraph system embodying a receiving and a sending station each radiating and receiving oscillations aty such different frequencies as to ynormally produc at each station an audible beat note, and each station having a key controlling both beat notes so that they are locally manifest only when both keys are in like positions, and means for preventing variation of the beat note due to movements of the operator.

16. Ina space radio telegraph system, two

radiating and receiving oscillations differing in frequency to simultaneously produce asignal currentl at each station, means for detecting the respective signal currents, and, "1- a key lat each station forvarying both signal currents.

17. The method of effecting two way space communication which consists in producing:

continuous waves of different frequency at each of two stations and radiating said n waves one to the other to produce at each station a signal current, detecting such signal current at each station and varying the circuit conditions at one station to effect a signal at both stations by variation of both signal currents. A .u

Signed at New York city, in the county of New York and State of New York, this14th day of. December, A. D. 1917.

` f PAUL WARE, 

